Contaminate sequestering coatings and methods of using the same

ABSTRACT

Contaminate-sequestering coatings including a network of hydrolyzed silane compounds including a plurality of thiol functional groups, a plurality of fluorinated functionalities, or both are provided. The contaminate-sequestering coatings may sequester one or more per- and polyfluoroalkyl substances (PFAS), heavy metals, biological species or any combination thereof. Methods of functionalizing a substrate surface with contaminate-sequestering functionalities that sequester one or more PFAS, heavy metals, or both are also provided. Methods of removing contaminants from contaminate-containing liquids, and devices including the contaminate-sequestering coatings are also provided.

STATEMENT OF GOVERNMENTAL INTEREST

This invention was made with Government support under contract numberN00024-13-D-6400 awarded by the Naval Sea Systems Command (NAVSEA). TheGovernment has certain rights in the invention.

TECHNICAL FIELD

Embodiments of the presently-disclosed invention relate generally tocontaminate-sequestering coatings, methods of functionalizing asubstrate surface with contaminate-sequestering functionalities (e.g., asurface functionalization technology that can be used on a variety ofsubstrates), methods of removing contaminants fromcontaminate-containing liquids, and devices including acontaminate-sequestering coating.

BACKGROUND

Clean water is a vital resource for life. This need has been realizedsince ancient times where civilizations would emerge and settle nearsources of clean water. With the growth of industrial, materials, andagrochemical production, the contamination of aquatic sources isbecoming more prevalent worldwide. Many contaminants have been reportedin water, including pesticides, heavy metal ions, biological species,pharmaceutical residues, and per- and polyfluoroalkyl substances (PFAS).In particular, PFAS (formerly known as perfluorochemicals) have emergedas an increasingly common contaminant in drinking water that are verydifficult to remove and persist in the environment due to their uniquestructures.

PFAS are synthetic compounds with multiple C—F bonds that are used inindustrial processes for the preparation of fire-resistant foams,protective coatings, and poly(tetrafluoroethylene) products.Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)are two eight-carbon PFAS that are widely found in water supplies. BothPFOS and PFOA are employed for a wide range of applications, includingaqueous film-forming foams for firefighting, nonstick cookware, andwater-resistant coatings for carpets, leather, and furniture. Due to thelong human body accumulation times for PFOS (5.4 years) and PFOA (3.8years), both chemicals have been linked to obesity, cancer, hormonedisruption, and high cholesterol levels.

PFOS and PFOA may be introduced into the environment from the wastestreams of industrial, military, or urban regions. The currentstate-of-the-art techniques for PFAS removal are adsorption on granularand powdered activated carbon, ion exchange resins, membrane filtration,and reverse osmosis. Of these approaches, adsorption on highlyporous-activated carbon is the most commonly used method today; however,this approach is both nonselective for PFAS with known limitations inremoving shorter chain PFAS and expensive to implement, which limits itsapplication for large-scale filtration.

Therefore, there remains a need in the art for a technology thatprovides sequestering of PFAS, such as PFOS and PFOA to name a few,present in a liquid (e.g., water) source.

SUMMARY OF INVENTION

One or more embodiments of the invention address one or more of theaforementioned problems. Certain embodiments according to the inventionprovide a contaminate-sequestering coating (e.g., in a dry state) thatcomprises a network of hydrolyzed silane compounds, in which thehydrolyzed silane compounds include a plurality of thiol functionalgroups, a plurality of fluorinated functionalities, or both.

In another aspect, certain embodiments of the invention provide a liquidcomposition comprising a flowable carrier medium and a plurality ofhydrolyzable silane compounds that include a plurality of thiolfunctional groups, a plurality of fluorinated functionalities, or both.

In another aspect, certain embodiments of the invention provide a methodof functionalizing a substrate surface with contaminate-sequesteringfunctionalities. In accordance with certain embodiments of theinvention, the method of functionalizing a substrate surface withcontaminate-sequestering functionalities includes covering an inorganicsubstrate with a liquid composition including a plurality ofhydrolyzable silane compounds that include a plurality of thiolfunctional groups, a plurality of fluorinated functionalities, or both.In accordance with certain embodiments of the invention, the method mayfurther comprise hydrolyzing the plurality of hydrolyzable silanecompounds to form a contaminate-sequestering coating on the inorganicsubstrate, in which the contaminate-sequestering coating comprises anetwork of the hydrolyzed silane compounds.

In another aspect, certain embodiments of the invention provide a methodof removing contaminants from a contaminate-containing liquid, in whichthe methods include contacting the contaminate-containing liquid with acontaminate-sequestering coating. In accordance with certain embodimentsof the invention, the contaminate-sequestering coating comprises anetwork of hydrolyzed silane compounds including a plurality of thiolfunctional groups, a plurality of fluorinated functionalities, or both.

In another aspect, certain embodiments of the invention provide a deviceincluding a substrate and a contaminate-sequestering coating bonded toat least a portion of the substrate, wherein thecontaminate-sequestering coating comprises a network of hydrolyzedsilane compounds including a plurality of thiol functional groups, aplurality of fluorinated functionalities, or both.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the invention now will be described more fullyhereinafter with reference to the accompanying drawings, in which some,but not all embodiments of the invention are shown. Indeed, thisinvention may be embodied in many different forms and should not beconstrued as limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will satisfy applicablelegal requirements. Like numbers refer to like elements throughout, andwherein:

FIG. 1 illustrates a schematic representation of a silanized substratehaving a network of hydrolyzed fluorosilanes sequestering/binding PFOAin accordance with certain embodiments of the invention;

FIG. 2 illustrates a fluorinated silane including an anchor region, afluorine-containing region, and a polar head region in accordance withone embodiment of the invention; and

FIG. 3 illustrates a schematic for a method of functionalizing asubstrate surface with contaminate-sequestering functionalities andsequestering PFAS in accordance with certain embodiments of theinvention.

DETAILED DESCRIPTION

Example embodiments of the invention now will be described more fullyhereinafter with reference to the accompanying drawings, in which some,but not all embodiments of the invention are shown. Indeed, thisinvention may be embodied in many different forms and should not beconstrued as limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will satisfy applicablelegal requirements. As used in the specification, and in the appendedclaims, the singular forms “a”, “an”, “the”, include plural referentsunless the context clearly dictates otherwise.

The presently-disclosed invention relates generally to acontaminate-sequestering coating (e.g., in a dry state) that comprises anetwork of hydrolyzed silane compounds, in which the hydrolyzed silanecompounds include a plurality of thiol functional groups, a plurality offluorinated functionalities, or both. The contaminate-sequesteringcoating may be deposited and/or bonded to a variety of substrates, suchas inorganic substrates typically used in, for example, filtration mediaand ion-exchange resins. In accordance with certain embodiments of theinvention, the network of hydrolyzed silane compounds having theplurality of thiol functional groups, the plurality of fluorinatedfunctionalities, or both may beneficially sequester a large array ofheavy metals and/or a large array of per- and polyfluoroalkyl substances(PFAS) (e.g., perfluorooctane sulfonic acid (PFOS) and perfluorooctanoicacid (PFOA)). Non-limiting examples of PFAS include perfluorohexanoicacid (PFHxA), perfluorononanoic acid (PFNA), perfluorohexanesulfonicacid (PFHxS), perfluoroheptanoic acid (PFHpA), Perfluorobutanesulfonicacid (PFBS), and GenX (e.g., a chemical process that uses2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid (FRD-903) andproduces 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate (FRD-902)and heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether (E1), in which thechemicals are used in products such as food packaging, paints, cleaningproducts, non-stick coatings, outdoor fabrics, and firefighting foam).

In accordance with certain embodiments of the invention, the acontaminate-sequestering coating may sequester or remove from about 50%to about 100% by weight of one or more PFAS and/or one or more heavymetal. In accordance with certain embodiments of the invention, forexample, the contaminate-sequestering coating may reduce the amount ofone or more PFAS present in a water stream or source to at or belowabout 80 parts-per-trillion, such as at or below about 70parts-per-trillion as recommended by the U.S. Environmental ProtectionAgency (EPA). By way of example only, FIG. 1 illustrates a schematicrepresentation of a silanized substrate having a network of hydrolyzedfluorosilanes sequestering/binding PFOA in accordance with certainembodiments of the invention. FIG. 1, for example, illustrates two (2)substrates 15 having a network of hydrolyzed fluorosilanes 10 bonded tothe substrate. FIG. 1 also illustrates that PFOS 20 and PFOA 22 aresequestered and retained within the network of hydrolyzed fluorosilanes.

In accordance with certain embodiments of the invention, the network ofhydrolyzed silane compounds is formed at least in part from ahydrolyzable thiol-functional silane according to Formula (I):

wherein

—OR₂, and —OR₃ are each hydrolyzable groups;

R₄ is a saturated C₁-C₂₀ radical or an unsaturated C₁-C₂₀ radical; and

X₁, X₂, and X₃ are each independently selected from —H, —SH, or a polargroup such as one or more ethylene glycol (EG) units; wherein at leastone of X₁, X₂, and X₃ is —SH.

In accordance with certain embodiments of the invention, R₁, R₂, and R₃from Formula (I) may each be independently selected from a C₁-C₄radical. In accordance with certain embodiment of the invention, the R₄from Formula (I) may include at least one side chain including thiolfunctionality thereon. In accordance with certain embodiment of theinvention, the R₄ from Formula (I) may include at least one heteroatomselected from oxygen, nitrogen, sulfur, phosphorus, or combinationsthereof.

By way of example only, the network of hydrolyzed silane compounds maybe formed from or comprise one of more of the following wherein ‘n’ maycomprise a value from 1 to about 20:

In accordance with certain embodiments of the invention, the contaminatesequestering coating comprises a network of hydrolyzed silane compoundsincluding a plurality of fluorine atoms. For example, the network ofhydrolyzed silane compounds may comprise one or more fluorinated silanecompounds comprising a linear C₁-C₂₀₀ perfluorosilane, for example, alinear perfluorosilane or combinations thereof having from at leastabout any of the following: 1, 3, 5, 8, 10, 12, 15, 20, 25, 30, 40, 50,60, 70, 80, 90, and 100 carbon atoms and/or at most about 200, 190, 180,170, 160, 150, 140, 130, 120, 110, 100, and 80 carbon atoms. Inaccordance with certain embodiments of the invention, for example, thenetwork of hydrolyzed silane compounds may be formed from or comprise aplurality of different perfluorosilane compounds having differing carbonchains (e.g., different lengths of the carbon chain to which fluorineatoms are bonded).

Additionally or alternatively, the network of hydrolyzed silanecompounds may include a fluorinated silane comprising a cyclichydrocarbon including from 3 to 200 carbon atoms and having one or morefluorine atoms (e.g., a fluorinated cyclic hydrocarbon). For example, acyclic hydrocarbon having one or more fluorine atoms may comprise atleast about any of the following: 1, 3, 5, 8, 10, 12, 15, 20, 25, 30,40, 50, 60, 70, 80, 90, and 100 carbon atoms and/or at most about 200,190, 180, 170, 160, 150, 140, 130, 120, 110, 100, and 80 carbon atoms.In accordance with certain embodiments of the invention, the cyclichydrocarbon having one or more fluorine atoms may comprise at least two(2) ring structures, such as at least about any of the following: 2, 3,4, 5, 6, and 8 ring structures and/or at most about 20, 18, 16, 14, 12,10, and 8 ring structures. In accordance with certain embodiments of theinvention, for example, the network of hydrolyzed silane compounds maybe formed from or comprise a plurality of different cyclic hydrocarbonshaving one or more fluorine atoms (e.g., different number of carbonatoms and/or different number of fluorine atoms).

Additionally or alternatively, the network of hydrolyzed silanecompounds may include a fluorinated silane comprising a non-linearfluorinated hydrocarbon including from 3 to 120 carbon atoms, such as adendrimer (e.g., molecules having repetitively branched structures thatmay or may not include cyclic rings within the molecular structure). Forexample, a fluorinated silane comprising a non-linear fluorinatedhydrocarbon may comprise at least about any of the following: 3, 4, 5,6, 8, 10, 12, 15, 18, 20, 25, 30, 40, 50, 60, 70, and 80 carbon atomsand/or at most about 200, 180, 160, 140, 120, 110, 100, 90, 80, and 70carbon atoms. In accordance with certain embodiments of the invention,for example, the network of hydrolyzed silane compounds may be formedfrom or comprise a plurality of different non-linear fluorinatedhydrocarbons (e.g., different number of carbon atoms and/or differentnumber of fluorine atoms).

In accordance with certain embodiments of the invention, the network ofhydrolyzed silane compounds may be formed or comprise fluorinatedsilanes, for example, as disclosed herein in which one or more of thefluorinated silanes include from about 4 to about 200 fluorine atoms,such as at least about any of the following: 4, 8, 10, 12, 15, 18, 20,30, 40, 50, 60, 70, 80, 90, and 100 fluorine atoms and/or at most aboutany of the following: 200, 180, 160, 140, 120, 100, 90, 80, 70, 60, and50 fluorine atoms. In accordance with certain embodiments of theinvention, for example, the network of hydrolyzed silane compounds maybe formed from or comprise a plurality of different fluorinated silaneshaving a different carbon-based backbone (e.g., different backbonelength and/or geometry—branched, linear, cyclic, etc.) and/or adifferent number of fluorine atoms. (e.g., different number of carbonatoms and/or different number of fluorine atoms).

In accordance with certain embodiments of the invention, the network ofhydrolyzed silane compounds may be formed or comprise one or morefluorinated silanes comprising a substituted hydrocarbon including atleast one heteroatom selected from oxygen, nitrogen, sulfur, phosphorus,or combinations thereof.

The network of hydrolyzed silane compounds, in accordance with certainembodiments of the invention, may be formed from (at least in part) orcomprise one or more fluorinated silanes that comprise (i) a polar headregion; (ii) a fluorine-containing region or a thiol-containing region;and (iii) an anchor region that forms a bond to a substrate (e.g.,inorganic substrate), in which the anchor region includes a siliconatom. In accordance with certain embodiments of the invention, thefluorine-containing region or thiol-containing region may be locatedbetween the polar head region and the anchor region. Thefluorine-containing region, for example, may comprise any fluorinatedhydrocarbon, such as those disclosed herein. For example, thefluorine-containing region may comprise a linear carbon backbone, anon-linear carbon backbone, a cyclic carbon backbone having a pluralityof fluorine atoms directly or indirectly bonded thereto. The carbonbackbone, for example, may be saturated or unsaturated. Additionally, oralternatively, the carbon backbone of the fluorine-containing region mayinclude at least one heteroatom selected from oxygen, nitrogen, sulfur,phosphorus, or combinations thereof. In accordance with certainembodiments of the invention, the fluorine-containing region maycomprise from about 4 to about 100 fluorine atoms, such as at leastabout any of the following: 4, 8, 10, 12, 15, 18, 20, 30, 40, 50, 60,70, 80, 90, and 100 fluorine atoms and/or at most about any of thefollowing: 200, 180, 160, 140, 120, 100, 90, 80, 70, 60, and 50 fluorineatoms. The thiol-containing region, for example, may comprise anythiol-containing hydrocarbon, such as those disclosed herein. Forexample, the thiol-containing region may comprise a linear carbonbackbone, a non-linear carbon backbone, a cyclic carbon backbone havinga plurality of thiol functional groups directly or indirectly bondedthereto. The carbon backbone, for example, may be saturated orunsaturated. Additionally, or alternatively, the carbon backbone of thethiol-containing region may include at least one heteroatom selectedfrom oxygen, nitrogen, sulfur, phosphorus, or combinations thereof. Inaccordance with certain embodiments of the invention, thethiol-containing region may comprise from about 1 to about 100 thiolfunctional groups, such as at least about any of the following: 1, 2, 3,4, 8, 10, 12, 15, 18, 20, 30, 40, 50, 60, 70, 80, 90, and 100 thiolfunctional groups and/or at most about any of the following: 200, 180,160, 140, 120, 100, 90, 80, 70, 60, and 50 thiol functional groups.

In accordance with certain embodiments of the invention, the polar headregion may comprise one or more polar functional groups to render thisportion of the compound more hydrophilic. The polar head region (e.g., ahydrophilic polar head), for example, may comprise one or more of one ormore of the following example functionalities: hydroxyl groups, carbonylgroups, alcohol groups, and sulfhydryl groups. The polar head region, inaccordance with certain embodiments of the invention, comprises one ormultiple units of ethylene glycol (EG) functionality (e.g., apolyethylene glycol (PEG) functionality). The polar head region, forexample, may comprise a plurality of PEG units in a linear structure ora branched structure. In accordance with certain embodiments of theinvention, the polar head region may comprise from 2 to 20 PEG units,such as at least about any of the following: 2, 3, 4, 8, 10, and 12, PEGunits and/or at most about any of the following: 20, 18, 16, 15, 14, and12 PEG units.

In accordance with certain embodiments of the invention, the anchorregion that forms a bond to a substrate (e.g., inorganic substrate), inwhich the anchor region includes a silicon atom, may comprise one ormore one or more hydrolyzable groups (e.g., alkoxy group) bonded to thesilicon atom. In accordance with certain embodiments of the invention,the anchor region may also include one or more heteroatom selected fromoxygen, nitrogen, sulfur, phosphorus, or combinations thereof.

FIG. 2, for instance, illustrates one fluorinated silane including apolar head region 100, a fluorine-containing region 110, and an anchorregion 120. For the specific fluorinated silane shown in FIG. 2, thepolar head region 100 includes four (4) PEG units to impart ahydrophilic region to the fluorinate silane. The fluorine-containingregion 110 comprises a perfluorinated region including 16 fluorineatoms. The anchor region 120 includes three (3) methoxy groups that canbe easily hydrolyzed to form a bond with a substrate (e.g., inorganicsubstrate) and to form the network of hydrolyzed silanes. The anchorregion 120 for this particular fluorinated silane also includes aheteroatom (i.e., nitrogen atom). It should be noted that FIG. 2 issimply an example and is not limiting.

In accordance with certain embodiments of the invention, the contaminatesequestering coating comprises a network of hydrolyzed silane compoundsinclude a first group of fluorinated silane compounds and a second groupof fluorinated compounds, in which the first group of fluorinated silanecompounds include from about 1.5 to about 10 times more fluorine atomsthan the second group of fluorinated compounds. In accordance withcertain embodiments of the invention, for example, the first group offluorinated silane compounds may comprise from at least about any of thefollowing: 1.5, 2, 3, 4, 5, and 6 times more fluorine atoms than thesecond group of fluorinated compounds and/or at most about any of thefollowing: 10, 9, 8, 7, 6, and 5 times more fluorine atoms than thesecond group of fluorinated compounds.

In accordance with certain embodiments of the invention, the contaminatesequestering coating comprises a network of hydrolyzed silane compoundsinclude a first group of thiol-containing silane compounds and a secondgroup of thiol-containing compounds, in which the first group ofthiol-containing silane compounds include from about 1.5 to about 10times more thiol groups than the second group of thiol-containingcompounds. In accordance with certain embodiments of the invention, forexample, the first group of thiol-containing silane compounds maycomprise from at least about any of the following: 1.5, 2, 3, 4, 5, and6 times more thiol groups than the second group of thiol-containingcompounds and/or at most about any of the following: 10, 9, 8, 7, 6, and5 times more thiol groups than the second group of thiol-containingcompounds.

In accordance with certain embodiments of the invention, the contaminatesequestering coating sequesters one or more polyfluoroalkyl (PFAS)compounds initially present in a liquid contaminated with an initialquantity of the PFAS compounds, in which an amount of the one or morePFAS compounds sequestered comprises from about 50% to about 100% byweight of the initial quantity of the PFAS compounds. In accordance withcertain embodiments of the invention, for example, the contaminatesequestering coating sequesters at least about any of the following: 50,60, 70, 80, and 85% by weight of an initial quantity of PFAS compoundsin a liquid and/or at most about any of the following: 100, 99, 98, 97,95, 90, 88, and 80% by weight of an initial quantity of PFAS compoundsin a liquid. In accordance with certain embodiments of the invention,the PFAS compounds comprise perfluorooctane sulfonic acid (PFOS),perfluorooctanoic acid (PFOA), or both.

In accordance with certain embodiments of the invention, the contaminatesequestering coating sequesters one or more heavy metals initiallypresent in a liquid contaminated with an initial quantity of the heavymetals, in which an amount of the one or more heavy metals sequesteredcomprises from about 50% to about 100% by weight of the initial quantityof the heavy metals. In accordance with certain embodiments of theinvention, for example, the contaminate sequestering coating sequestersat least about any of the following: 50, 60, 70, 80, and 85% by weightof an initial quantity of heavy metals in a liquid and/or at most aboutany of the following: 100, 99, 98, 97, 95, 90, 88, and 80% by weight ofan initial quantity of heavy metals in a liquid. In accordance withcertain embodiments of the invention, the heavy metals comprise mercury(Hg), cadmium (Cd), arsenic (As), chromium (Cr), thallium (Tl), lead(Pb), or any combination thereof.

In accordance with certain embodiments of the invention, the contaminatesequestering coating may be disposed onto a variety of substrates, suchas an inorganic substrate. Non-limiting examples of suitable substratesmay include a variety of filtration media, such as an aluminum oxidehydroxide (γ-AlOOH) mineral. In accordance with certain embodiments ofthe invention, the substrate comprises a filtration medium that maycomprise an aluminum oxide hydroxide (γ-AlOOH) mineral attached tomicro-glass strands (e.g., an AHLSTROM DISRUPTOR® 4603 filter). Inaccordance with certain embodiments of the invention, the filtrationmedium may comprise an ultra-filter medium, a nano-filter medium, or areverse osmosis membrane. The substrate may also comprise, for example,an ion-exchange resin. In accordance with certain embodiments of theinvention, the substrate comprises an aluminum oxide hydroxide (γ-AlOOH)mineral that may sequester or bind one or more biological species, suchas Escherichia coli (E. Coli) and/or virus bacteriophage MS2. Inaccordance with such embodiments of the invention, an initial quantityof one or more biological species may be reduced (e.g., sequester,removed, etc.) from at least about any of the following: 50, 60, 70, 80,and 85% by weight of an initial quantity of the biological species in aliquid and/or at most about any of the following: 100, 99, 98, 97, 95,90, 88, and 80% by weight of an initial quantity of biological speciesin a liquid. In accordance with certain embodiments of the invention, acombination of one or more PFAS, one or more heavy metals, and one ormore biological species may simultaneously be reduced (e.g., sequester,removed, etc.) from at least about any of the following: 50, 60, 70, 80,and 85% by weight of an initial quantity thereof in a liquid and/or atmost about any of the following: 100, 99, 98, 97, 95, 90, 88, and 80% byweight of an initial quantity thereof in a liquid.

In another aspect, certain embodiments of the invention provide a liquidcomposition comprising a flowable carrier medium and a plurality ofhydrolyzable silane compounds that include a plurality of thiolfunctional groups, a plurality of fluorinated functionalities, or bothas disclosed herein. In accordance with certain embodiments of theinvention, the flowable carrier medium may comprise an organic solvent,an alcohol, or an aqueous-based solvent (e.g., water). The liquidcomposition, for example, may comprises a solution, suspension, orcolloid including a plurality of hydrolyzable silane compounds thatinclude a plurality of thiol functional groups, a plurality offluorinated functionalities, or both as disclosed herein. In accordancewith certain embodiments of the invention, the hydrolyzable silanecompounds may comprise from about 0.01% to about 20% by weight of theliquid composition, such as at least about any of the following: 0.01,0.05, 0.1, 0.5, 1, 3, 5, 8, 10, and 12% by weight of the liquidcomposition and/or at most about 20, 18, 15, 12, and 10% by weight ofthe liquid composition. The liquid composition, for example, may beshipped to a point of use or produced on-site (i.e., a point of use) andapplied to a substrate (e.g., filter media, ion exchange resin, etc.) toprovide a contaminate sequestering coating thereon.

In this regard, certain embodiments of the invention also provide amethod of functionalizing a substrate surface withcontaminate-sequestering functionalities. In accordance with certainembodiments of the invention, the method of functionalizing a substratesurface with contaminate-sequestering functionalities includes coveringa substrate (e.g., an inorganic substrate) with a liquid compositionincluding a plurality of hydrolyzable silane compounds that include aplurality of thiol functional groups, a plurality of fluorinatedfunctionalities, or both. In accordance with certain embodiments of theinvention, the method may further comprise hydrolyzing the plurality ofhydrolyzable silane compounds to form a contaminate-sequestering coatingon the substrate (e.g., silanization of the substrate's surface), inwhich the contaminate-sequestering coating comprises a network of thehydrolyzed silane compounds as disclosed herein. In accordance withcertain embodiments of the invention, the substrate coated or coveredwith the liquid composition may include a variety of filtration media,such as an aluminum oxide hydroxide (γ-AlOOH) mineral. In accordancewith certain embodiments of the invention, the substrate may comprise afiltration medium that may comprise an aluminum oxide hydroxide(γ-AlOOH) mineral attached to micro-glass strands (e.g., an AhlstromDisruptor® 4603 filter). In accordance with certain embodiments of theinvention, the filtration medium may comprise an ultra-filter medium, anano-filter medium, or a reverse osmosis membrane. The substrate mayalso comprise, for example, an ion-exchange resin.

FIG. 3, for example, illustrates a schematic for a method offunctionalizing a substrate 15 surface with contaminate-sequesteringfunctionalities 10 and sequestering PFAS 20, 22 in accordance withcertain embodiments of the invention, in which the substrate comprisesan aluminum oxide hydroxide (γ-AlOOH) mineral that may simultaneouslysequester or binds one or more biological species 26, such asEscherichia coli (E. Coli) and/or virus bacteriophage MS2.

In accordance with certain embodiments of the invention, the step ofcovering a substrate (e.g., an inorganic substrate) with a liquidcomposition including a plurality of hydrolyzable silane compounds thatinclude a plurality of thiol functional groups, a plurality offluorinated functionalities, or both may comprise submerging thesubstrate within the liquid composition, which may be housed within avessel or pumping the liquid composition over the surface of thesubstrate and/or through the thickness of the substrate (e.g., pumpingthe liquid composition through a filter media or through a bed ofion-exchange resin). In accordance with certain embodiments of theinvention, the step of covering the substrate with the liquidcomposition may comprise contacting the substrate with the liquidcomposition for at least about 0.5 minutes to about 120 minutes, such asat least about any of the following: 0.5, 1, 5, 10, 15, 25, 30, 40, 50,60, 70, 80, and 90 minutes and/or at most about 120, 110, 100, 90, 80,and 70 minutes.

In accordance with certain embodiments of the invention, the method offunctionalizing a substrate surface with contaminate-sequesteringfunctionalities may further comprise adding a total amount of thehydrolyzable silane compounds as disclosed herein to the flowablecarrier. In accordance with certain embodiments of the invention, thehydrolyzable silane compounds may comprise from about 0.01% to about 20%by weight of the liquid composition, such as at least about any of thefollowing: 0.01, 0.05, 0.1, 0.5, 1, 3, 5, 8, 10, and 12% by weight ofthe liquid composition and/or at most about 20, 18, 15, 12, and 10% byweight of the liquid composition. In accordance with certain embodimentsof the invention, the step of adding the total amount of thehydrolyzable silane compounds to a flowable carrier comprises selectingthe total amount of hydrolyzable silane compounds to provide at least amonolayer coverage of the surface area with the network of thehydrolyzed silane compounds.

In accordance with certain embodiments of the invention, the method offunctionalizing a substrate surface with contaminate-sequesteringfunctionalities may further comprise cleaning the substrate (e.g.,inorganic substrate) prior to covering the substrate (e.g., inorganicsubstrate) with the liquid composition. For example, the step of washingthe base surface with alcohol, acetone, toluene and the like, the stepof cleaning the substrate (e.g., inorganic substrate) may compriseoxygen plasma treating the substrate prior to contacting the substratewith the liquid composition having a plurality of hydrolyzable silanecompounds that include a plurality of thiol functional groups, aplurality of fluorinated functionalities, or both. Cleaning (e.g.,pre-treating the surface of the substrate) the substrate may facilitatesilanization of the substrate.

In another aspect, certain embodiments of the invention provide a methodof removing contaminants from a contaminate-containing liquid, in whichthe methods include contacting the contaminate-containing liquid with acontaminate-sequestering coating. In accordance with certain embodimentsof the invention, the contaminate-sequestering coating comprises anetwork of hydrolyzed silane compounds including a plurality of thiolfunctional groups, a plurality of fluorinated functionalities, or both.In accordance with certain embodiments of the invention, thecontaminate-containing liquid comprises water. In accordance withcertain embodiments of the invention, the contaminate-containing liquidcomprises water including (i) one or more polyfluoroalkyl (PFAS)compounds, (ii) one or more heavy metals, or both (i) and (ii).

In accordance with certain embodiments of the invention, thecontaminate-containing liquid may be pumped across and/or through thesubstrate either as a single pass or multiple passes (e.g.,recirculating the contaminate-containing liquid through a filter orion-exchange bed including the contaminate-sequestering coating) until adesired reduction in PFAS and/or heavy metals is realized. In accordancewith certain embodiments of the invention, the contaminate-sequesteringcoating sequesters from about 50% to about 100% by weight of an initialquantity of the PFAS compounds, an initial quantity of the heavy metals,or both. In accordance with certain embodiments of the invention, forexample, the contaminate-sequestering coating sequesters at least aboutany of the following: 50, 60, 70, 80, and 85% by weight of an initialquantity of PFAS compounds in a liquid and/or at most about any of thefollowing: 100, 99, 98, 97, 95, 90, 88, and 80% by weight of an initialquantity of PFAS compounds in a liquid. In accordance with certainembodiments of the invention, the PFAS compounds compriseperfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), orboth. In accordance with certain embodiments of the invention, forexample, the contaminate-sequestering coating sequesters at least aboutany of the following: 50, 60, 70, 80, and 85% by weight of an initialquantity of heavy metals in a liquid and/or at most about any of thefollowing: 100, 99, 98, 97, 95, 90, 88, and 80% by weight of an initialquantity of heavy metals in a liquid. In accordance with certainembodiments of the invention, the heavy metals comprise mercury (Hg),cadmium (Cd), arsenic (As), chromium (Cr), thallium (Tl), lead (Pb), orany combination thereof.

In accordance with certain embodiments of the invention, the method ofremoving contaminants from a contaminate-containing liquid comprisesreducing PFOS and/or PFOA to less than about 80 parts-per-trillion(ppt), such as less than about 75 ppt, less than 70 ppt, less than 60ppt, or less than 50 ppt.

In another aspect, certain embodiments of the invention provide a deviceincluding a substrate (e.g., an inorganic substrate) and acontaminate-sequestering coating bonded to at least a portion of thesubstrate, wherein the contaminate-sequestering coating comprises anetwork of hydrolyzed silane compounds including a plurality of thiolfunctional groups, a plurality of fluorinated functionalities, or bothas described herein.

In accordance with certain embodiments of the invention, the substratemay include a variety of filtration media, such as an aluminum oxidehydroxide (γ-AlOOH) mineral. In accordance with certain embodiments ofthe invention, the substrate may comprise a filtration medium that maycomprise an aluminum oxide hydroxide (γ-AlOOH) mineral attached tomicro-glass strands (e.g., an AHLSTROM DISRUPTOR® 4603 filter). Inaccordance with certain embodiments of the invention, the filtrationmedium may comprise an ultra-filter medium, a nano-filter medium, or areverse osmosis membrane. The substrate may also comprise, for example,an ion-exchange resin. In accordance with certain embodiments of theinvention, the device may comprise a housing structuring that directlyor indirectly secures the substrate in a particular location or region.For example, the device may comprise a pressure vessel that securesand/or confines the substrate therein while also providing a feed inletthat allows a liquid source (e.g., a contaminate-containing liquid) andan outlet for allowing the liquid source to exit the pressure vesselafter passing over and/or through the substrate, in which thecontaminates (or a majority of the contaminates as disclosed herein)present within the liquid source entering the pressure vessel aresequestered on the contaminate-sequestering coating bonded to at least aportion of the substrate. In accordance with certain embodiments of theinvention, the device may comprise a filter cartridge.

EXAMPLES

The present disclosure is further illustrated by the following examples,which in no way should be construed as being limiting. That is, thespecific features described in the following examples are merelyillustrative and not limiting.

A commercial γ-AlOOH filtration media AHLSTROM DISRUPTOR® 4603 wasprovided by Ahlstrom Filtration LLC (Mt Holly Springs, Pa.). The filtermedia was used without further pretreatment. Oxygen plasma treatment wasaccomplished using a Harrick Plasma Cleaner PDC-001. Commercialperfluorosilanes and 3-aminopropyl trimethoxysilane were obtained fromGelest Inc. (Morrisville, Pa.) and used in the as-received form. PFOS,PFOA, trifluorotoluene, NOVEC® 7100, and ethanol were obtained fromSigma-Aldrich (St. Louis, Mo.) and used without any furtherpurification. Reagents for synthesis were obtained from Sigma-Aldrich orOakwood Chemicals and used as received. Anhydrous solvents werepurchased from Sigma-Aldrich. FILTRASORB® 300 granular activated carbonwas obtained from Calgon Carbon Corporation (Moon Township, Pa.).

Surface Functionalization:

Two functionalization procedures were developed for filterfunctionalization. All silane functionalization reactions were performedin plastic containers.

(1) Fluorinated Silane Functionalization:

The base filter was 4603, which consists of γ-AlOOH nanowhiskerssintered onto fiberglass and forming a nonwoven filter. The effectivepore size in these filters is around 1 All filters were subjected to anoxygen plasma treatment for 20 min. The filters were then placed in a 1%(v/v) solution of silane in trifluorotoluene with 0.1% (v/v) acetic acidand placed on a shaker table for 24 h (150 rpm). The filters werecollected by vacuum filtration, washed with trifluorotoluene andisopropanol, and dried under vacuum.

(2) PEG-Fluorinated Silane Functionalization:

The 4603 filters were subjected to an oxygen plasma treatment for 20min. The filters were then placed in a 1% (v/v) solution of silane in95% ethanol with 0.1% (v/v) acetic acid and placed on a shaker table for24 h (150 rpm). The filters were collected by vacuum filtration, washedwith ethanol, and dried under vacuum.

Water Filtration Tests:

Artificial water solutions containing PFOS and PFOA were prepared withdeionized water spiked with a target 860 ppt of PFOS and 390 ppt of PFOAaccording to the NSF method 53. The pH of the water was controlled to bearound 7.5. Two types of filtration testing were performed: (a) dynamicfiltration test: a filter with a diameter of 25 mm, a thickness of 0.67mm, and an average weight of 120 mg was encapsulated inside a 25 mmfilter holder made of polycarbonate. A flux of 1223 L/m²·h was selectedusing the recommended flow rate based on NSF protocol P248 (MilitaryOperations Microbiological Water Purifiers) as well as NSF P473-2016(drinking water treatment units, PFOA and PFOS). Prior to collecting thesample, the filter was flushed with the challenge water for 100 mL, andthen a total of 200 mL sample was collected. The total filtration timewas around 30 minutes. To avoid any cross-contamination, all testingtubing was fluorine-free. (b) Batch-mode filtration test: this test wasperformed by soaking three filters (the same size as used in the dynamicfiltration process) in Erlenmeyer flasks containing 15,000 ppt PFOS and8800 ppt PFOA in deionized water. The flask was then placed on a shakertable for 48 h operated at 200 rpm at room temperature. After thedesired duration, the concentration of PFOS and PFOA of the water wasthen analyzed and the adsorption capacity was then calculated.

For relative comparison, granular activated carbon (GAC) was ground toless than 250 μm in particle size to fit inside the polycarbonate filterholder. Approximately 60 mg of GAC was supported onto the 4603 basemembrane for the dynamic state testing. The empty bed contact time wasaround 1 second using the empty bed divided by the flow rate of 10mL/min. The bed volume after the sample collected was around 0.16 mL.

PFOS and PFOA Testing:

PFOS and PFOA were analyzed using solid phase extraction (SPE) andLC/MS/MS according to the EPA method 537 version 1.1 (2009). Briefly,the C13 labeled analogs of the target compounds were added to the samplecontainer. The container was agitated, and then the contents of thecontainer (water sample) were passed through a solid phase extraction(SPE) cartridge with a weak anion exchange (WAX) sorbent. Once the PFAScompounds were adsorbed onto the WAX cartridge, the cartridge was elutedwith the solvent and the solvent solution was reduced in volume. Analiquot of the final volume was then injected onto an LC/MS/MS operatedin electrospray ionization, negative ion mode. Target analytes were thenquantified off of a primary transition ion used to generate acalibration curve of relative response (target/isotope) versusconcentration. The minimum reporting levels (MRLs) for PFOS and PFOA are0.4 and 0.2 ppt, respectively.

Synthesis of PEG Silanes:

Compounds 3, 4a, 4b, 5a, and 5b from Scheme 1 below were preparedaccording to literature procedures. Briefly, a solution oftetraethyleneglycol monomethyl ether (10.0 g, 48.0 mmol) andtriethylamine (6.8 mL, 48.0 mmol) in CH₂Cl₂ (100 mL) was treated withp-toluenesulfonyl chloride (8.70 g, 45.6 mmol) portionwise at 20° C.under nitrogen. The resulting reaction mixture was stirred for 16 h at20° C. The reaction was diluted with water (200 mL), and the aqueouslayer was extracted with CH₂Cl₂ (150 mL×2). The combined organicfractions were dried (MgSO₄) and concentrated under reduced pressure toyield tosylate 3 (15.2 g, 41.9 mmol, 87%) as a colorless oil. HNMR (400MHz; CDCl₃): δ 7.80 (d, J=8.2 Hz, 2H), 7.34 (d, J=8.0 Hz, 2H), 4.16 (t,J=4.8 Hz, 2H), 3.68 (t, J=4.9 Hz, 4H), 3.63 (t, J=4.5 Hz, 8H), 3.58 (s,5H), 3.54 (t, J=4.6 Hz, 3H), 3.37 (s, 3H), 2.45 (s, 3H).

General Procedure for the Alkylation of Fluorinated Diols: A solution ofdiol 4a-c from Scheme 1 below (14.5 mmol) in dry dioxane (50 mL) wastreated with sodium hydride (60% dispersion in mineral oil, 10.4 mmol)under nitrogen, stirred for 30 min at room temperature, and warmed to90° C. for 2 h. A solution of tosylate 3 (6.90 mmol) in dry dioxane (19mL) was added dropwise and the mixture was stirred at 90° C. overnight.The reaction was cooled down to room temperature and quenched with 1 MHCl (2 mL), and the solvent was removed under reduced pressure. Thecrude compound was dissolved in dichloromethane (200 mL), and a whiteprecipitate was removed via filtration. After solvent removal, the crudeproduct was purified by chromatography on SiO₂ (2:1 ethylacetate/hexanes) to yield 5a0-c from Scheme 1 as the monosubstitutedalcohols.

16,16,17,17,18,18,19,19,20,20,21,21,22,22,23,23-Hexade-cafluoro-2,5,8,11,14-pentaoxatetracosan-24-ol(5c from Scheme 1). H NMR (400 MHz; CDCl₃): δ 4.13-3.99 (m, 4H),3.79-3.77 (m, 2H), 3.66 (q, J=7.7 Hz, 12H), 3.56-3.52 (m, 2H), 3.38 (s,3H); 19F NMR (376 MHz, CDCl₃): δ=−123.5 (s), −122.4, −122.0, −119.8.

General Procedure for Triflation and Aminolysis of Alcohols:

A solution of PEG-fluorinated alcohol 5a-c from Scheme 1 (2.41 mmol) indry THF (5 mL) was cooled to 0° C. and treated with trifluoromethanesulfonyl chloride (4.83 mmol) followed by triethylamine (6.03 mmol)under a N₂ atmosphere. The reaction was stirred for 30 min at 0° C. andallowed to warm to room temperature overnight, diluted with EtOAc, andwashed with water. The organic extract was dried (MgSO₄), filtered, andconcentrated in vacuo to give the crude product. The crude product waspurified by chromatography on SiO₂ (1:1 to 4:1 ethyl acetate/hexanes) togive the intermediate triflate as a tan, oily liquid. The intermediatetriflate (2.41 mmol) was dissolved in 3-amino-propyltrimethoxy silane(7.25 mmol) and heated to 50° C. overnight. The reaction wasconcentrated to a viscous oil, and silanes 1a-c were carried on directlyfor the functionalization of the membranes.

Results

In these examples, γ-AlOOH filtration media was used and investigatedfor the feasibility of fluorinated surface functionalization for PFOSand PFOA removal from contaminated water. The γ-AlOOH substrate waschosen due to its high specific surface area as well as its surfacecharacteristics upon contact with water. That is, in aqueous solutions,the aluminol group on γ-AlOOH leads to the formation of (Al(OH))²⁺. As aresult, γ-AlOOH carries a high level of positive charge and is commonlyused to sequester negatively charged microbes from water. In accordancewith certain embodiments of the invention, therefore, a multifunctionalfiltration media that can simultaneously remove toxic heavy metal ions,biological species, and PFOS/PFOA from water is provided.

The initial approach for the removal of PFOA and PFOS was based on thetheory, to which we do not wish to be bound, that the perfluorinatedside chains, for example, would have a favorable fluorophilic C—F . . .F—C interaction and adsorb onto a surface functionalized withperfluorinated chains as illustrated in FIG. 1. Using commercialperfluorinated silanes, 4603 filters were functionalized and tested forthe removal of PFOA and PFOS. The silanes utilized to functionalize the4603 filters were (tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane (F13), (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxy-silane (F17), and(perfluoro(polypropyleneoxy))-methyoxypropyl trimethoxysilane(F133-283). Structures for (tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane (F13), (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxy-silane (F17), and(perfluoro(polypropyleneoxy))-methyoxypropyl trimethoxysilane (F133-283)are shown below:

Several functionalization conditions for the functionalization of 4603filters with fluorinated silanes include solvents, temperatures, andreaction times. One set of functionalization conditions (95% EtOH, cat.AcOH) resulted in filters that performed poorly on these substrates,presumably due to the aggregation of the silanes in solution, whichprevented efficient functionalization of the substrate. Asperfluorinated compounds are often soluble in fluorinated solvents, wetested trifluoroethanol, trifluorotoluene (TFT), and NOVEC® 7700 forfilter conjugation and found that using TFT as the solvent yieldedfilters with the highest removal of PFOA and PFOS. Functionalizationusing NOVEC® 7700 yielded filters with the second best removal.

A silane concentration screen of the F17-functionalized filters wastested under dynamic filtration conditions at silane concentrations of0.1, 0.5, and 1%, and the results are shown in Table 1 below. PFASremoval improved with increasing silane concentration but also resultedin a large pressure drop. This is most likely due to the increasedhydrophobicity of the filters.

TABLE 1 Dynamic Filtration using Silanes silane total pressure loadingPFOS/PFOA PFOS PFOA drop samples (%) (ppt) (ppt) (ppt) (psi) challengewater N/A 1250 860  390 4603 control 0 239 29 210 1.0 F13 on 4603 1.0 96<MRL 96 1.2 F17 on 4603 0.1 86  1 85 1.3 F17 on 4603 0.5 16 <MRL 16 2.9F17 on 4603 1.0 3  1 2 4.6 GAC on 4603 0 167 47 120 0.6

These fluorinated silane-modified filters performed better than a filterloaded with a cake layer of granular activated carbon (GAC) FILTRASORB®300. Compared to the F13 silanized filter, the F17 silanized filterdisplayed almost quantitative removal at a similar silane loading. Notethat the higher performance of the fluorinated silane-modified filtersin this test may have been due to faster kinetics rather than highercapacity since the empty bed contact time of 1 s is less than thetypical GAC empty bed contact time for PFAS (>10 min).

Subsequently, improving the filter performance was achieved by reducingthe back pressure under increased flux. The highly fluorinated surfaceproduced high back pressure and negatively impacted filtrationefficiency. It was hypothesized that a silane containing a polar, forexample, poly(ethylene glycol) (PEG) terminus (i.e., polar head regionpreviously discussed herein) and a perfluorinated region wouldeffectively reduce any associated pressure drop while maintaining theeffective removal of PFAS. The structure of this amphiphilic silane isshown in FIG. 2.

A series of silanes with varied perfluorinated chains were preparedaccording to Scheme 1. The MPEG-4-0H (2) was activated using tosylchloride. The diol (4a-c from Scheme 1) was deprotonated using sodiumhydride and alkylated with the tosylate (3 from Scheme 1) to providealcohol (5a-c from Scheme 1) in modest yields. Alcohols 5a-c from Scheme1 were activated as the triflate using trifluoro-methane sulfonylchloride and displaced with 3-aminopropyl trimethoxysilane at 50° C. togive the desired products (1a-c from Scheme 1) in good yields. Analogswere prepared with 4-, 6-, and 8-perfluorinated carbons giving 8, 12,and 16 fluorines, respectively. Compounds 1a-1c from Scheme 1 were useddirectly for the filter conjugation reaction without furtherpurification. Interestingly, these products were soluble under ourinitial conjugation conditions (95% EtOH, cat. AcOH) and did not requirethe use of fluorinated solvents.

Beneficially, the PEG-substituted fluorosilanes proved highly effectivein removing PFOA and PFOS with no increase in pressure drop as shown inTable 2 below. Overall, the PEG silanes with fluorination lengths ofF8-F16 were highly effective in removing PFOS/PFOA with the F16-PEGsilane (1c) performing the best overall.

TABLE 2 PFAS Removal under Dynamic Conditions silane total pressureloading PFOS/PFOA PFOS PFOA drop samples (%) (ppt) (ppt) (ppt) (psi)challenge N/A 1250 860 390 4603 control 0 239 29 210 1.0 F17 on 4603 1.03 1 2 4.6 1a on 4603 1.0 91 2 89 0.8 1b on 4603 1.0 0.7 0 0.7 1.0 1c on4603 1.0 0.4 0 0.4 0.6

Batch-Mode Adsorption for PFOA and PFOS:

A static batch-mode adsorption experiment was performed at 25° C. withPFOA and PFOS challenge solutions and the 4603 control,F17-functionalized 4603, and 1c-functionalized 4603 (F16-4PEG), using achallenge solution with 15,000 ppt PFOS and, 8800 ppt of PFOA. The totaltime of the experiment was controlled to be 48 h. The results are shownin Table 3 below. Functionalization with silane 1c resulted in thehighest adsorption of PFOA under the batch-mode conditions, and the F17had the highest adsorption of PFOS with almost complete removal from thechallenge solution. The high adsorption capacity of PFOS is believed tobe due to the extra fluorine atoms, which can lead to morefluorine-fluorine interactions, and the results are consistent with ourmolecular dynamic (MD) simulation. Preliminary data suggests thatadsorbed PFOS and PFOA do not leach out of used filters when flushedwith deionized water,

TABLE 3 Static Adsorption of PFOA and PFOS PFOS PFOA PFOS adsorptionPFOA adsorption adsorption adsorption capacity increase capacityincrease capacity capacity over 4603 control over 4603 control samples(ng/mg) (ng/mg) (%) (%) 4603 3124 15 F17 12 565   57 302 280 F16-4PEG9963 148 219 887

Filters functionalized with commercial fluorinated silanes proved highlyeffective at removing PFAS contaminants from the challenge water,however, resulting in a large pressure drop. To improve the performanceof these filters, a series of modified amphiphilic silanes weresynthesized and evaluated under dynamic and static filtrationconditions. Beneficially, these silanes provided excellent PFAS removalwith no increased pressure drop. The amphiphilic silanes have a highcapacity for PFAS removal under static adsorption conditions.

Additional PFAS Removal Study:

An additional set of studies were performed under dynamic flowconditions in the manner disclosed above, in which the flow rate was 10ml/min with a flux of 1223 L/hr*m² at 23° C. In this regard, a challengesolution containing 1000 ppt of PFOS and 500 ppt of PFOA was utilizedfor testing of a variety of filters and functionalized filters. Thecontrol was a 4603 base filter, which consists of γ-AlOOH nanowhiskerssintered onto fiberglass and forming a nonwoven filter. The effectivepore size in these filters is around 1 μm. An additional comparativetest included loading approximately 60 mg of GAC supported onto the 4603base membrane for the dynamic state testing. A 4603 filter wasfunctionalized with a F17 silane, in accordance with certain embodimentsof the invention, with the following structure and tested:

Also tested was a 4603 filter was functionalized with a F16-4PEG silane,in accordance with certain embodiments of the invention, with thefollowing structure and tested:

The results are shown in Table 4 below.

TABLE 4 Additional PFAS Removal under Dynamic Conditions PFOS PFOSPressure PFOS PFOA Removal Removal Drop Samples (ppt) (ppt) (%) (%)(psi) challenge 1000 500 NA NA 4603 control 310 365 69 27 0.5 F17 on4603 0 4 100 98.6 4.2 F16-4PEG: 4603 0 0.7 100 99.9 0.6 GAC F300 47 12090 94 1.0

As shown in Table 4, the functionalized filters in accordance withcertain embodiments of the invention effectively sequestered all of thePFOA and the PFOS in the challenge water, while the fluorinated-silaneincluding the polar head region provided a pressure drop similar to orless than traditional filtering technologies that fail to provide thelevel of PFOA and PFOS sequestering.

These and other modifications and variations to the invention may bepracticed by those of ordinary skill in the art without departing fromthe spirit and scope of the invention, which is more particularly setforth in the appended claims. Specifically, for example, it should beunderstood that additional example embodiments include a method ofremoving contaminants from a contaminate-containing liquid, where themethod includes contacting the contaminate-containing liquid with acontaminate-sequestering coating, where the contaminate-sequesteringcoating includes a network of hydrolyzed silane compounds including aplurality of thiol functional groups, a plurality of fluorinatedfunctionalities, or both. Moreover, in the foregoing additional exampleembodiment, the contaminate-containing liquid may include water thatincludes: (i) one or more polyfluoroalkyl (PFAS) compounds: (ii) one ormore heavy metals; (iii) biological species; or (iv) any combination of(i), (ii) and (iii). Even further, the contaminate-sequestering coatingmay sequester from about 50% to about 100% by weight of: (i) an initialquantity of the PFAS compounds; (ii) an initial quantity of the heavymetals; (iii) an initial quantity of biological species; or (iv) anycombination of (i), (ii), and (iii). Yet another example embodimentincludes a device, which includes a substrate and acontaminate-sequestering coating bonded to at least a portion of thesubstrate, where the contaminate-sequestering coating includes a networkof hydrolyzed silane compounds including a plurality of thiol functionalgroups, a plurality of fluorinated functionalities, or both, and furtherwhere the substrate includes a filtration medium or an ion-exchangeresin.

In addition, it should be understood that aspects of the variousembodiments may be interchanged in whole or in part. Furthermore, thoseof ordinary skill in the art will appreciate that the foregoingdescription is by way of example only, and it is not intended to limitthe invention as further described in such appended claims. Therefore,the spirit and scope of the appended claims should not be limited to theexemplary description of the versions contained herein.

What is claimed is:
 1. A contaminate-sequestering coating, comprising anetwork of hydrolyzed silane compounds including a plurality of thiolfunctional groups, a plurality of fluorinated functionalities, or both;wherein at least one of the hydrolyzed silane compounds includes a polargroup comprising one or more ethylene glycol (EG) units.
 2. Thecontaminate sequestering coating of claim 1, wherein the network ofhydrolyzed silane compounds includes a fluorinated silane comprising alinear C₁-C₄₀ perfluorosilane.
 3. The contaminate sequestering coatingof claim 1, wherein the network of hydrolyzed silane compounds includesa fluorinated silane comprising a cyclic hydrocarbon including from 3 to60 carbon atoms.
 4. The contaminate sequestering coating of claim 1,wherein the network of hydrolyzed silane compounds includes afluorinated silane including from 4 to about 200 fluorine atoms.
 5. Thecontaminate sequestering coating of claim 1, wherein the network ofhydrolyzed silane compounds includes a fluorinated silane comprising asubstituted hydrocarbon including at least one heteroatom selected fromoxygen, nitrogen, sulfur, phosphorus, or combinations thereof.
 6. Thecontaminate sequestering coating of claim 1, wherein the network ofhydrolyzed silane compounds includes a first group of fluorinated silanecompounds and a second group of fluorinated compounds, and wherein thefirst group of fluorinated silane compounds includes from about 1.5 toabout 5 times more fluorine atoms than the second group of fluorinatedcompounds.
 7. The contaminate sequestering coating of claim 1, whereinthe contaminate sequestering coating sequesters: (i) one or morepolyfluoroalkyl (PFAS) compounds initially present in a liquidcontaminated with an initial quantity of the PFAS compounds, wherein anamount of the one or more PFAS compounds sequestered comprises fromabout 50% to about 100% by weight of the initial quantity of the PFAScompounds; (ii) one or more heavy metals initially present in a liquidcontaminated with an initial quantity of the heavy metals, wherein anamount of the one or more heavy metals sequestered comprises from about50% to about 100% by weight of the initial quantity of the heavy metals;or (iii) both (i) and (ii).